With the advent of ubiquitous computing, machine-to-machine (M2M) communication technology has been spotlighted. The M2M communication technology is under study in many standard development organizations (SDOs) including TIA, ATIS, and ETSI. M2M technology is mainly about communication between an M2M server part and an M2M client or M2M device (hereinafter, referred to as M2M device) part. In most cases, communication is performed between a small number of M2M servers and a large number of M2M devices and thus communication overload may be caused to a network between the two entities. Since most M2M devices are battery-based communication devices, a technology of increasing the time period during which a device stays in the power save mode or sleep mode is important in reducing battery consumption or power consumption in the M2M communication environment.
Communication frequently occurring between an M2M device and an M2M server is performed to periodically read the value of a sensor in the M2M device and report the value to the M2M server.
In terms of device management (DM) of managing portable terminals or electronic devices, implementation of an M2M communication system primarily creates an environment in which many servers having different functions manage one device or terminal. For example, a software-managing server, a firmware-managing server, a virtualizing device-managing server and the like manage one device or terminal. In an environment in which several servers are present and a server is added or deleted, there is a need for a process of a particular server granting a right to manage a certain device to another server. For example, when an account of a server for managing firmware is added to a particular terminal, the server needs to grant a right to manage the firmware to a client of the particular terminal.
Regarding grant of a right as above, conventional device management (DM) technology includes a delegation protocol. The delegation protocol includes a delegation process and a delegation revocation process. Through the delegation process, an access right to a certain part of a DM tree of a client within a particular terminal is granted to a server. Through the delegation revocation process, the access right to a certain part of the DM tree of the client within the particular terminal that is granted to the server is deleted.
In the real environment, delegation/delegation revocation may be divided into two cases. In the first case, delegation/delegation revocation occurs semi-permanently. For example, delegation to the server of a particular mobile carrier may occur when a particular terminal join the mobile carrier, and delegation revocation may occur when the terminal is disjoined. In the second case, delegation/delegation revocation frequently occurs. For example, when a terminal enters a building of a company, it receives DM service from the server of the company (delegation). When the terminal moves out of the company building, the server of the company interrupts the DM service (delegation revocation).
For the second case, using conventional delegation/delegation revocation complicates the processing processes such as setting/deleting an access right and storing/deleting information about a server and causes excessive computation in the client within the terminal. Accordingly using the conventional delegation/delegation revocation is not preferable. That is, in the case in which delegation and delegation revocation are frequently repeated, a processing technique simpler than the conventional technology is needed.
The present invention proposes delegation and delegation revocation techniques optimized for an environment in which delegation/delegation revocation frequently occur as in the second case.